Most files labeled as "GTA 4 PSP" are actually heavily modified versions of GTA: Liberty City Stories
While you cannot play Niko Bellic’s story on a PSP, you have two excellent alternatives that are fully compatible and safe to play (assuming you own the games). Gta 4 Psp Zip
If you encounter a .zip or .iso file claiming to be GTA 4 for the PSP or PPSSPP emulator , it is almost certainly one of the following: : A mod for GTA: Liberty City Stories or GTA: Vice City Stories Most files labeled as "GTA 4 PSP" are